1. Field of the Invention
The present invention relates to a color filter substrate, an electrophoretic display (“EPD”) device having the color filter substrate, and a method thereof. More particularly, the present invention relates to a color filter substrate capable of enhancing white luminance characteristics, an EPD device having the color filter substrate, and a method of enhancing a white luminance characteristic of the EPD device.
2. Description of the Related Art
FIG. 1 is a schematic diagram showing a conventional electrophoretic display (“EPD”) device.
Referring to FIG. 1, in general, an EPD device has a reflect type structure that displays images by reflecting lights applied from an external side. The EPD device includes white ink particles 1 negatively charged, black ink particles 2 positively charged, microcapsules 5 surrounding transparent organic flowing substances 3, and binders surrounding and combining the microcapsules 5, that are disposed between two electrodes.
When an electric field is applied to the two electrodes, the white ink particles 1 move towards a view direction to display white images in a white state and the black ink particles 2 move towards the view direction to display black images in a black state. That is, lights applied from an external side are reflected by the white ink particles 1 that move towards the view direction, so that images are displayed.
The EPD device has a reflect type structure that displays images using lights applied from an external side, so that a contrast ratio (“C/R”) of the EPD device is relatively low.
The EPD device is a type of flat panel display device that is commonly used for displaying an electronic book. The EPD device includes two panels having field-generating electrodes and a plurality of microcapsules 5 arranged between the panels. Each microcapsule 5 includes electric ink containing a plurality of white and black pigment particles 1, 2 that are respectively charged negatively and positively. When an electric field is applied to the microcapsules 5, the white and black particles 1, 2 move in opposite directions to display images.
The EPD device has high reflectance and high contrast regardless of the viewing angle, making reading from the EPD device substantially the same as reading from a paper image. In addition, the EPD device does not require polarizers, alignment layers, liquid crystal, etc., which are expensive components of a liquid crystal display (“LCD”).
However, since dispersing the white and black ink particles 1, 2 with bi-stability in the microcapsule 5 is complicated, the manufacturing process and the production cost thereof are disadvantageous. Also, a separate color filter is required to display the image with full color.